This invention relates to an assisted steering device for a vehicle, comprising control means acting on direction changing means, the said control means having a transmission element in two parts which are capable of limited relative angular movement which permits angular offsetting of the said parts under the action of the said control means, and assistance means which, in response to such angular offsetting, are operable to act on the direction changing means in the same sense as the control means.
The invention relates more particularly to a device of this kind in which the said assistance means comprise a hydraulic station, a hydraulic jack acting on the said direction changing means and a hydraulic distributor interposed between the station and the jack.
The invention relates more particularly to a distributor of the type comprising an axial stack consisting of a first stator, a first rotor disc integral in rotation with one of the two parts of the transmission element, a second rotor disc integral in rotation with the other part of the transmission element, and a second stator, the first stator being supplied by the said hydraulic station, the first rotor disc having a series of passages, the second rotor disc having two series of passages, and the second stator supplying the said hydraulic jack.
The known devices of this kind are generally complex in construction, requiring the use of a balancing or equilibrating piston and elastic means for taking up the play along the interfaces between the stators and rotors, which means that, in particular, the stator associated with the hydraulic station has to be mounted so as to slide in an axial direction. Despite such structural arrangements, the rotor discs are thick and badly balanced and are found to suffer from operational difficulties. Moreover, the rotors have to be machined differently on each of their two surfaces, thus making manufacture more complicated.
The invention provides an assisted steering device for a vehicle which does not suffer from these disadvantages, which is extremely simple in construction and which operates satisfactorily in a perfectly balanced manner.